import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;

public class CopyAndWrite {
    public static void main(String[] args) {
        CopyOnWriteArrayList<String> copy = new CopyOnWriteArrayList<>();
        ConcurrentHashMap<Object, Object> map = new ConcurrentHashMap<>();

    }
}
